I'm not sure how you get a non-stoichimetric cell with a multiplicative
number of unit cells, unless you said you want to repeat the atom at z=0.
Of course, without this extra layer, you may not have inversion and get
2 different surface terminations in one calculation. This is the usual
problem of slabs.
Also symmetry will be reduced and "multiplicity" errors occur. But both,
nn and sgroup create new struct files where this has been corrected.
If possible, I would also go to a smaller number of layers.
Am 24.07.2023 um 10:13 schrieb Burhan Ahmed:
That is very true. I made the slab using the tutorial available in the
wien2k user manual by executing x-supercell program. What I found is
that the 6ql supercell consist of an extra Te atom. But whenever I try
to remove this atom I got multiplicity error. Sir, what is best possible
way of making slab with vacuum or surfaces??
Thanks
Regards
Burhan Ahmed
*Research Scholar, AUS *
*From: *Laurence Marks <mailto:laurence.ma...@gmail.com>
*Sent: *Saturday, July 22, 2023 6:30 PM
*To: *A Mailing list for WIEN2k users
<mailto:wien@zeus.theochem.tuwien.ac.at>
*Subject: *Re: [Wien] calculation with lmbj potential
Others will probably give you suggestions about converging mBJ. Some
deeper comments.
The most common reason that calculations behave badly is user error.
Sometimes this is doing the initialization wrong, often it is creating
an inappropriate model. Just because one can use x supercell or related
codes to create atomic positions does /not/ make them sensible.
Your slab has a composition Bi12 Te19, i.e. it is Te rich. You therefore
have a reduced, n-type semiconductor with a small gap (about 0.1eV)
which will behave badly. If you look at your BVS you will see that atom
Te7 is severely underco-ordinated (unstable).
I doubt that your slab will ever converge to anything which should be
published. Surfaces are not simple, it is unfortunately too easy to set
something up and get it wrong. (There are many papers in the literature
of dubious merit.)
On Fri, Jul 21, 2023 at 10:47 PM Burhan Ahmed <burhan.ah...@aus.ac.in
<mailto:burhan.ah...@aus.ac.in>> wrote:
Dear experts, I am doing an scf calculation taking lmbj potential.
My system is a slab of 6ql with a vacuum of 40 ang along c-axix.
Whenever I try to run the scf calculation including SOC, after 999
iteration the scf is still not converged. I have analyzed the scf
file, it shows the fluctuating nature. At first the selected Rmt was
2.5 then I reduces it to 2.34 and again convergence failed after 999
cycle. I have included -hdlo and -lvns 8 switch in init_lapw as it
shows heavy atom. I am attaching the case.struct file. Hoping for
any suggestion/solution.
Regards
Burhan Ahmed
*Research Scholar, AUS *
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Professor Laurence Marks (Laurie)
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu <http://www.numis.northwestern.edu>
"Research is to see what everybody else has seen, and to think what
nobody else has thought", Albert Szent-Györgyi
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